What firewall/router do you prefer to use?

I have setup an old PC running IPfire and an old router running as an AP for the wifi in order to keep costs down, but I do intend to buy a nice wifi card for the PC in the not to distant future and let the old PC control all aspects of the network.

What do you prefer to use, do you use a linux/unix based firewall, or a standard router, or with a custom ROM?

Let me know in the comments.